Threats to at-risk salmonids of the Canadian Rocky Mountain region     

R. Niloshini Sinnatamby  Ariane Cantin  John R. Post 《Ecology of Freshwater Fish》2020,29(3):477-494

Trout and charr, members of the salmonid family, have high conservation value but are also susceptible to anthropogenic threats in part due to the specificity of their habitat requirements. Understanding historical and future threats facing these species is necessary to promote their recovery. Of freshwater trout and charr in the Canadian Rocky Mountain region, westslope cutthroat trout (Oncorhynchus clarkii lewisi), bull trout (Salvelinus confluentus; a charr species) and Athabasca rainbow trout (Oncorhynchus mykiss) are of conservation concern. And indeed, range contractions and declining populations are evident throughout much of their ranges. Range contraction was most evident in the southern Alberta designatable unit (DU) of westslope cutthroat trout. Diminished populations were also evident in the downstream watersheds of the Alberta bull trout range, and throughout the Athabasca rainbow trout range. We assessed historical and future threats to evaluate the relative importance of individual threats to each DU and compare their impact among species. Individual threats fall into the broad categories of angling, non-native species and genes, habitat loss and alteration, and climate change. Severity of each threat varies by DU and reflects the interaction between species’ biology and the location of the DU. Severity of threats facing each DU has changed over time, reflecting extirpation of native populations, changes in management and industry best practices, expansion of non-native species and progressing climate change. The overall threat impact for each DU indicates a high probability of substantial and continuing declines and calls for immediate action.  相似文献   

不同种源多穗柯主要生物活性成分与矿质元素含量变异分析     

何平  厉月桥  刘儒  喻龙华  冯慧  谢健杨 《中南林业科技大学学报(自然科学版)》2021,(1)

【目的】阐明多穗柯主要药用活性成分与矿质元素的种源遗传变异规律。【方法】对设置在江西省分宜县多穗柯全分布区的5个种源试验林植株叶部根皮苷、三叶苷、总黄酮、有机碳、氮、磷和钾元素含量进行测定、分析。【结果】不同种源多穗柯叶部根皮苷、三叶苷、总黄酮、有机碳、全氮、全磷含量差异均存在极显著差异(P <0.01)。不同种源根皮苷含量变异范围为16.03~64.35 mg·g-1,三叶苷含量变异范围分别为4.76~29.97 mg·g-1,根皮苷含量变异范围为61.59~81.05 mg·g-1,其中重庆北碚为根皮苷、有机碳、全磷和全氮含量高的种源,与其他种源相比根皮苷含量最高,四川米易三叶苷含量最高,江西分宜总黄酮含量最高。多穗柯根皮苷含量随日照时数增加呈显著降低趋势(P <0.05),三叶苷含量随无霜期增加呈显著降低趋势,总黄酮含量随经度增加呈极显著增加的趋势,随降水量增加呈显著增加的趋势;根皮苷与全氮含量呈极显著正相关关系,有机碳与全钾含量呈显著负相关关系;聚类分析表明,5个多穗柯种源可划分为2个类群,高根皮苷、高总黄酮、低三叶苷类群和低根皮苷、低总黄酮和高三叶苷类群。【结论】多穗柯根皮苷、三叶苷、总黄酮和主要矿质元素含量具明显种源变异,重庆北碚、四川米易和江西分宜的多穗柯为优良种源。  相似文献   

Predicting the potential geographic distribution of Bactrocera bryoniae and Bactrocera neohumeralis(Diptera: Tephritidae) in China using MaxEnt ecological niche modeling          下载免费PDF全文

Jing Wan  QI Guo-jun  MA Jun  Yonglin Ren  WANG Rui  Simon MCKIRDY 《农业科学学报》2020,19(8):2072-2082

Bactrocera bryoniae and Bactrocera neohumeralis are highly destructive and major biosecurity/quarantine pests of fruit and vegetable in the tropical and subtropical regions in the South Pacific and Australia. Although these pests have not established in China, precautions must be taken due to their highly destructive nature. Thus, we predicted the potential geographic distribution of B. bryoniae and B. neohumeralis across the world and in particular China by ecological niche modeling of the Maximum Entropy(Max Ent) model with the occurrence records of these two species. Bactrocera bryoniae and B. neohumeralis exhibit similar potential geographic distribution ranges across the world and in China, and each species was predicted to be able to distribute to over 20% of the globe. Globally, the potential geographic distribution ranges for these two fruit fly species included southern Asia, the central and the southeast coast of Africa, southern North America, northern and central South America, and Australia. While within China, most of the southern Yangtze River area was found suitable for these species. Notably, southern China was considered to have the highest risk of B. bryoniae and B. neohumeralis invasions. Our study identifies the regions at high risk for potential establishment of B. bryoniae and B. neohumeralis in the world and in particular China, and informs the development of inspection and biosecurity/quarantine measures to prevent and control their invasions.  相似文献   

细叶桉不同立地种源试验   总被引：1，自引：0，他引：1  

陶德生 《浙江林业科技》1996,16(2):1-15

应用细叶桉２５个地理种源进行了２批不同立地种源试验，对４－６年生幼林生长表现和适应性，运用指数分析法进行评价，结果表明：强轩桉种源间各怀状差异，山地片达到显著或极显著水平，平地片除第２批材积差异显著外，其余均不显著。  相似文献   

杉木优良种源在苏南低山丘陵地区的推广应用     

/Lu xiangsheng et al. 《江苏林业科技》1996,23(2):10-13

本文报道了杉木优良源在江苏南部低山丘陵地区推广的背景和依据，组织体系，措施与配套技术，推广情况及其经济，生态，社会效益。  相似文献   

The Application of GIS in Small Watershed Classification in Loess Plateau     

Zhu Jinzhao  Wu Bin  Bi Huaxing  Zhou Changqing College of Soil  Water Conservation  Beijing Forestry UniversityBeijing  P.R.China 《中国林学(英文版)》1994,(2)

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Spatial distribution of Aspergillus flavus and its toxigenic strains on commercial cottonseed from south Texas and its relationship to aflatoxin contamination     

R. Jaime-Garcia  P. J. Cotty 《Plant pathology》2006,55(3):358-366

The structure of Aspergillus flavus communities associated with south Texas cottonseed was determined by analysing samples from 178 truckloads of commercial cottonseed from 35 gins, extending from Fort Bend County in the north to the Rio Grande Valley in the south, from September 1999 to October 2001. The number of colony-forming units (CFU) of A. flavus on the cottonseed, and the percentage of S strain (%S) were both correlated with aflatoxin contamination of cottonseed. The number of CFU differed between both regions and seasons, while %S differed only between regions. Comparison of maps of CFU and %S revealed that CFU shows a higher variation across years, while %S shows higher spatial variation. The Rio Grande Valley had significantly lower CFU and %S strain than the Coastal Bend and Upper Coast regions. Cottonseed produced in 1999 had significantly more A. flavus than that produced in either 2000 or 2001. Identification of factors dictating geographical variation in S-strain incidence may provide insights that will lead to improved aflatoxin management.  相似文献   

安徽省绩溪县竹种及分布   总被引：3，自引：0，他引：3  

黄成林  赵昌恒 《竹子研究汇刊》1993,12(3):20-28

  相似文献   

福建土壤对酸沉降的相对敏感性评价与区划     

樊后保 《福建林学院学报》2001,21(3):198-202

选择母岩、土壤类型、土地利用和降雨量 4个生态因子 ,应用半定量化方法对其进行类目划分和权重 ,综合评价了福建省土壤对酸沉降的相对敏感性 ,并应用地理信息系统进行了区划 .由于福建省风化缓慢的硅质岩所占的比例较大 ,土壤大多呈酸性至微酸性反应 ,降水丰富 ,加之针叶林面积大 ,所以全省有 60 %以上面积的土壤显示出较大的敏感性等级 (5～ 7级 )  相似文献   

《蒙古秘史》中的野生食用植物研究   总被引：7，自引：1，他引：6  

哈斯巴根 《干旱区资源与环境》1996,10(1):87-96

经考证,在《蒙古秘史》中的植物古蒙古名称中,有山荆子、稠李、地榆、鹅绒委陵菜、葱、山韭、山丹和野韭等８种野生食用植物。植物区系及地理分布的研究表明,这些植物在十二世纪蒙古人所采集的地点,即现在的蒙古国肯特山脉地区仍有广泛分布。从民族植物学的研究看,它们在蒙古族民间被用于代粮、野菜、茶用、药用和调味品,比过去的利用有了很大的发展,已成为独特的植物利用文化。本文不仅对蒙古学研究能够提供可靠的依据,而且对寻找新的食用植物种类及其开发利用研究也提供了一些基本资料。  相似文献